SGER: Comparative Studies of Senescence in Natural Populations of Guppies

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9986801 ReznickThis is a comparative study of aging in natural populations of guppies based on individually mark as many as 2,000 guppies each from two populations. One population is from an environment where they naturally experience low mortality rates, so that they have high life expectancies. The other population was recently introduced from a high mortality rate environment to a low mortality rate environment, where differences in mortality rate are caused by differences in the predators that guppies co-occur with. This second population has already evolved to some extent in response to the lower mortality rates in the new environment. A recently developed statistical test will determine if there is an acceleration in mortality rates in the oldest age classes of guppies and hence if there are differences among these two populations in the rate of acceleration of mortality rate, i.e., senescence. Theory predicts that there should be differences in the rate of senescence in these two populations. The broader goal is to determine why animals age from an evolutionary perspective. While hundreds of investigators are studying aging, very few are considering why we see differences among populations or species in the rate of aging, even though a theory predicting why such differences evolve was proposed over 40 years ago. This study tests these predictions.